Inorganic-organic hybrid materials that include metal-organic frameworks (“MOFs”) have attracted intensive attention in recent years. MOFs are known to display the highest reported specific surface area among all porous materials, and can be synthesized from a theoretically infinite combination of metals and linkers. This has made them promising candidates for a diverse range of applications including sensing, separation, and drug delivery.
To establish a thorough structure-property relationship for rational MOF design, numerous studies have explored different functions of various MOFs (e.g., such as for gas storage, sensing, and separation), however few studies have focused on MOF semiconductor materials and properties. Research aimed at exploring the tuning of semiconductor behaviors of MOFs have generally focused on band gap energy variation by changing the different metals and/or linkers involved in the synthesis (see for example Yang, L. M.; Fang, G. Y.; Ma, J.; Ganz, E.; Han, S. S. Cryst. Growth Des. 2014, 14, 2532-2541, and Hendon, C. H.; Tiana, D.; Fontecave, M.; Sanchez, C.; D'arras, L.; Sassoye, C.; Rozes, L.; Mellot-Draznieks, C.; Walsh, A. J. Am. Chem. Soc. 2013, 135, 10942-10945). Some structure to property relationship studies have shown that varying organic linkers can significantly impact the bulk optical band gap energy (see for example Gascon, J.; Hernández-Alonso, M. D.; Almeida, A. R.; van Klink, G. P. M.; Kapteijn, F.; Mul, G. ChemSusChem 2008, 1, 981-983).
Numerous studies have been performed focusing on varying the ligand to change optical band gap energy, however these attempts were mostly made before synthesis (see for example Flage-Larsen, E.; Royset, A.; Cavka, J. H.; Thorshaug, K. J. Phys. Chem. C 2013, 117, 20610-20616, and Lin, C.-K.; Zhao, D.; Gao, W.-Y.; Yang, Z.; Ye, J.; Xu, T.; Ge, Q.; Ma, S.; Liu, D.-J. Inorg. Chem. 2012, 51, 9039-9044). Furthermore, the modification of the optical band gap energy through internal in-situ reactions using controllable external stimuli has not been widely explored.